A kingmaker is a person or group that has great influence in a royal or political succession, without being a viable candidate. Kingmakers may use political, monetary, religious, and military means to influence the succession. Originally, the term applied to the activities of Richard Neville, 16th Earl of Warwick—"Warwick the Kingmaker"—during the Wars of the Roses (1455-1487) in England.
In game theory, a kingmaker is a player who lacks sufficient resources or position to win at a given game, but possesses enough remaining resources to decide which of the remaining viable players will eventually win.
The term "Kingmaker", though always unofficial, has tended to gain more importance in places of power struggle—e.g., politics, sports organizations etc. Consequently, bestowal of such a title is looked upon significantly and more often as a means of indirect gratification for individuals wanting to silently dictate the affairs of the organization. The term is also occasionally used in a pejorative sense during elections, where a small number of independent political candidate(s) who hold a sizeable sway in the "vote bank", can most likely decide the course of an outcome.
Instead of referring to an individual, the term can also be applied to institutions or think tanks whose opinions are held in great regard by the interested organization. The influence of the religious orders like the Roman Catholic Church in running the affairs of the state during medieval times (through the King) is a well-known example. Kingdoms and empires in the Indian sub-continent often relied on their religious heads. Besides religious orders, even countries can fit into this terminology when they can dictate the affairs of the other country (either directly or indirectly). In current political scenarios across the world the term can expand its scope to include powerful lobbying groups, whose role is often seen as a defining factor on major issues.
Citizens of West Africa's constituent monarchies often use the word kingmaker to refer to the members of the electoral colleges that choose their sovereigns because they also usually officiate during the coronation rituals and rites of purification, the word in this particular case taking on a literal meaning i.e.: a Maker of the king.
The term "Kingmaker" is also used to describe situations in multi-player games where a player is either unable to win or has claimed an unassailable lead, but, in either case, plays a strong role in determining the outcome for other players.